Automatic pattern controlled milling machine



April 1936- B. sAssEN ET AL. 2,036,362

AUTOMATIC PATTERN CONTROLLED MILLING MACHINE Filed Sept. 20, v1932 8SheetsSheet l J MTM gun/002mm;

April 7, 1936,. 1%. $A$$EM m m... x'mmwez AUTOMATIC PATTERN CONTROLLEDMILLING MACHINE Filed Sept. 20, 1932 8 Sheets-Sheet B gin/Um;

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8 Sheets-Sheet 3 April 7, 1936 B. 'sAgsfim AUTOMATIC PATTERN CONTROLLEDMILLING MACHINE Filed Sept. 20, 1932 April 1936. E. sAssEN El ALAUTOMATIC PATTERN CONTROLLED MILLING MACHINE Filed Sept. 20, 1932 8Sheets-Sheet 4 SrWC/YM} BERNARD 5A55N HANS ERNST April 7, B. SASSEN ETAL AUTOMATIC PATTERN CONTROLLED MILLING MACHINE Filed Sept 20, 1952 8Sheets-Sheet 5 April 7, 193., 5mm

AUTOMATIC PATTERN CONTROLLED MILLING MACHINE Filed Sept. 20, 1932 8Sheets-Sheet 6 WNY m KWN WU WM;

,BEANARDSASSEN HANS ERNST AUTOMATIC PATTERN CONTROLLED MILLING MACHINEFiled Sept; 20, .1952

Sizeeisfiheet 7 HANS ERA/5T April 1936- B. $A$$EN ET AL AUTOMATICPATTERN CONTROLLED MILLING MACHINE 8 Sheets-Sheet 8 Filed Sept. 20, 1.93

HANS ERA 57' ANQULM IDSPLACEMENT 0F TRACER HEAD Watentcd Apr. 7, 193$apron/rare Bernard Sassen and Hans Ernst, Cinciati, Ohio, assignors toThe Cincinnati Milling Machine grfimpany, hlncinnati, Ohio, acorporation cl I Application September 20, 193%, Serial No. dtdflld toClaim.

. forming tracer movement into relative movement between cutter andwork, whereby pattern controlled milling operations heretofore deemedim- 7 possible may be successfully and efiiciently performed and wherebycontours requiring relative angular movement through angles greater orless than a complete circle-may be reproduced automatically in acontinuous operation.

In automatic pattern controlled machines of the past and moreparticularly those used for profiling purposes, it has been necessary inoperations requiring an angular movement through more than 180 degreesto make directional adjustments usually at the completion of eachquadrant of movement in order to insure a constant urge of the tracertoward the pattern and thus maintain the tool in proper position withrespect to the-work. These adjustments were not effectible automaticallythereby necessitating the attention of theoperator to make them and although made quickly, yet a new stress condition was created in themachine which sufficiently varied the relation between the cutter andwork to cause undesirable marks to be left on the finished surface whichhad to be removed by subsequent finishing operations.

One of the principal objects of this invention therefore is to providean automatic pattern controlled milling machine suitable for die-sinkingor profiling purposes which will automatically effect a cut throughangles as great as 360 degrees or even greater without the necessity ofany manual diriehti'llhal adjustments thereby providing a finishedsurface which is free from undesirable tool marks.

In any type of pattern controlled machine tool it has always been deemednecessary to have the tracer of substantially the same diameter as thecutter in order to insure that each will bear the same relationship tothe pattern and work respectively at all times in order to insurefaithful reproduction of irregular contours. This results in a certainhardship because it is difiicult to maintain the cutter of equaldiameter to the tracer, especially where the cutter must be groundperiodically to maintain a proper cutting edge. furthermore, cutters ofthe exact diameter suitable for the work, or for the size of tracers athand may not always be available.

Therefore, another object of this invention is to overcome theinadequacies of prior structures l. till-13.5)

by providing greater flexibility in the selection of cutters that may beused with a given diameter oi tracer, especially those used in planeprofiling and die-sinking operations.

Still another object of this invention is to provide a tracerconstruction which is adjustable in such a manner that variable stockallowances over the size of the pattern may be left and for such othernecessary adjustments as may arise from sharpening the cutter.

Another inadequacy of prior structures is the impossibility of producinga female die directly from a duplicate male pattern, or a male die froma female pattern because the performance of this function would havenecessitated the use of a tracer and cutter of zero diameter. Thisinvention has therefore as one oi? its objects to overcome thisdifficulty by providing an improved tracer mechanism that will makepossible the formation of a male or female die from its counter part.

An additional object of this invention is to provide a rotary tracercontrolled mechanism for determining the direction of relative feedbetween cutter and work and one which bears such a relationship to theoperated parts that a suitable pointer may be incorporated therewith toindicate progressively any change in the direction of resultant movementoccurring between cutter and work.

Another important object of this invention is to provide a universalhydraulically actuated pattern controlled milling machine which may beutilized for profiling or die-sinking purposes under either automatic ormanual control without the necessity of making special adjustments tothe machine for either purpose or method of operation.

Another object of this invention is to provide a machine of the type setforth in which the tracer may be automatically brought into properoperating contact with the pattern without attention on the part of theoperator.

A still further object of this invention is to provide an improvedmethod of die-sinking whereby a die may be formed in one continuouscutting operation thereby insuring a high degree of fidelity betweenpattern and work.

Other objects and advantages of the present invention should be readilyapparent by reference to the following specification ccnsidered inconjunction with the accompanying drawings illustrative of oneembodiment thereof, but it will be understood that any modifications maybe made in the specific structural details thereof within the scope ofthe appended claims without departing from or exceeding the spirit ofthe invention.

Referring to the drawings in which like reference numerals indicate likeor similar parts:

Figure l is a front elevation of a machine embodying the principles ofthis invention.

Figure l-A is a side view of the machine as viewed from the left ofFigure 1.

Figure 2 is a side elevation of the machine as viewed from the right ofFigure 1.

Figure 3 is a section on the line 3--3 of Figviews showing the variouspositions of the tracer mechanism during automatic positioning of thetracer into contact with the master.

Figure 17 is a diagram of the hydraulic circuit of the machine.

Figure 17A is a. diagram showing orientation of cylinder motors.

Figure 18 is a diagram showing relation between tracer and pattern, andcutter and work.

Figure 19 is a view of a modified form of tracer button.

Figure 20 is a view showing relation of pattern and tracer when turninga corner in the pattern.

Figure 21 is a section showing the dividing wall between balancingvalves.

Figures 22, 23 and 24 are views showing the different positions of thedistributor valve.

Figures 25 to 29 inclusive are sectional views through the directionalcontrol valve taken on the respective section lines in Figure 6.

Figure 30 is a section on the line 30--30 of Figure 29.

Figure 31 is a section similar to Figure 30 but with the valve memberturned through an angle of 45 degrees from the position shown in Figure29.

Figure 32 is a sectional view on the line 3232 of Figure 26 but with thevalve turned through an angle of 45 degrees from that shown in Figure26.

Figure 33 is a graph showing the relation between angular displacementof the tracer head to the quantity of flow effecting the displacements.

Figure 34- is an expanded view showing the graduations on the tracerhead.

Figures 35 and 36 are diagrammatic views showing the relative positionsof tracer and cutter for producing male or female parts from theircounterparts.

Figure 37 is a section on the line CIT-31 of Figure 2.

Figure 38 is a detail of the detent mechanism as viewed on line 38-38 ofFigure 3'7.

Figure 39 is a sectional view on the line 39-49 of Figure 37.

In the art of pattern controlled profiling, diesinking and the like, itis necessary to set upand maintain a fixed relationship between thecutter and tracer in accordance with the relative spacing between thepattern and work, and so connect the tracer with the cutter thatdeflection of one will cause a corresponding relative adjustment of theother to the end that the pattern will be faithfully reproduced in thework. If this adjustment is accomplished by power means, then that meansmust be placed under the control of the tracer in such a manner that itwill automatically respond to each deflection imparted to the tracer bythe pattern. In addition, machines of the automatic type are providedwith means for constantly urging the tracer into contact with thepattern in order that it may detect and respond to variations in thecontour thereof. In present machines this urge can only be maintained inone direction at a time and thus it is customary to change the directionof this urge manually for each quadrant of operation. If now this urgecould always be maintained in a direction perpendicular to the tangentpassing tln'ough the point of contact between tracer and pattern thenthis manual adjustment would not be necessary and continuous millingthrough an angle of 360 degrees or greater could be accomplished withoutattention on the part of the operator.

One of the important features of this invention is to provide tracercontrolled mechanism which will function in such a manner as to maintainsubstantially this perpendicular relationship automatically throughout acomplete orbit of engagement with the' pattern, or through angles evengreater than 360 degrees. In order that this feature of the inventionmay be more thoroughly understood, and for the purpose of explanationlet it be assumed that a pattern I G and Work piece II are mounted insuitable spaced relation as shown diagrammatically in Figure 18, thework piece to be finished to the exact size of the pattern. The centerof the cutter is indicated by the reference numeral I3. Let the lineY--Y' be drawn perpendicular to the surface of the pattern through apoint I2 which is maintained in fixed relationship with the center ofthe cutter I3; the line Y-Y be drawn through the center I3 parallel tothe line Y-Y', and the line X-X' be drawn through the points I2 andI3'perpendicular to the line Y--Y'. If the distance from the point I2 tothe pattern along line YY is equal to the radius of the cutter, then thecutter will be tangent to the desired finished surface of the work; orin other words, the distance from the point I2 to the pattern is equalto the distance from the center of the cutter to the work. If nowrelative movement is produced between the pattern and tracer so that thepoint I2 moves along the path I4 and the line Y-Y' is maintainedperpendicular at all times to the tangent at the point I 5, the cutter,if maintained in fixed relationship with the point I2, will follow apath I 6, of similar shape to the path I4, and a work piece will beproduced having the same outline as the pattern, and of equal dimensionstherewith. These dimensions may, however, be made slightly larger orsmaller as when providing for finish stock allowance, by making thedistance I 2-I5 slightly smaller or larger respectively than the radiusof the cutter.

Mom this simple diagram it will be seen that the tracer could be a shortarm of length I2-I5 terminating in a point or knife edge and makingpoint or line contact with the pattern and. need not therefore be acircular member of equal diameter with the cutter. Furthermore, if thelength of this arm with respect to the center I2 is variable, it will beapparent that this tracer means and for that reason it is generalpractice to mount the tracer for universal movement.

In the present construction, as previously mentioned, it is notnecessary that the tracer button have the same diameter as the cutterbut it may be any amount greater than the cutter and in certain casesmay be even smaller than the cutter. Also, in the present construction,the tracer need not even be mounted for universal movement; all of whichwill be explained more fully hereafter. Although the tracer buttonitself may be of larger diameter than the cutter, its center maynevertheless lie on the line Y-Y as at the point i'l when undeflected.If the tracer button, represented by the circle I8 for convenience, isnow deflected by the pattern its center will move alongthe line Y-Y suchas to the point i 9, and

l the distance between H and I9 will indicate the amount of tracerdeflection. This deflection may be considered to be the amount requiredto move the tracer to a neutral position, and thus make it possible forthe tracer to deflect either positively or negatively with respect tothis position; otherwise, if the tracer had no initial deflection whenin contact with the pattern, it could only respond to departures in thepattern surface which were toward the tracer as represented by the line22 in Figure 18 and not those which receded therefrom as represented bythe line 2i.

It is also apparent from this diagram that the only thing that canchange the amount of deflection of the tracer button would be adeparture of the pattern surface from parallelism with the line X-X'.For instance, when the point of con: tact it has moved to the corner 20of the pattern the tracer, if properly urged toward the pattern, will beundeflected, or in other words will be moved slightly toward the centerof the pattern. The point of tangency would then lie on the inclinedface 2| in which case the line Y--Y' would not at that instant beperpendicular to this face. In other words, a deflection of the tracereither toward or away from the pattern may be said to break momentarilythe perpendicular relationship of the line YY' with respect to thepattern. Also, due to the continued movement of the point I! in adirection parallel to the line X--X', the distance between I! and pointof tangency would be greater than before and the distance between it andit which is the tracer deflection will thus be decreased. This decreasein tracer deflection is utilized to reestablish the requiredperpendicular relationshipso that the center of the cutter i3 willproperly follow the path it. One way that this can be brought about isto mount the tracer button in a rotary tracer head having its axis atthe point l2 and then rotating the tracer head until the line Y--Y'realigns itself perpendicular to the surface 2i. It is thus apparentthat means must be provided for rotating the tracer head and furthermorethat the direction of this rotation must depend upon whether the newpath of travel is in a direction such as the line 2!, which will causewhat will be herein known as undeflection of the tracer, or whether itis in the direction of a surface, such as 22, which would cause whatwill herein be termed as increased deflection of the tracer. If asurface, such as 2!, causes undeflection of the tracer, the tracer headmust be rotated in a countor-clockwise direction, or in other words in adirection indicated by the arrow 23, while if a surface, such as 22,causes increased deflection, the head must be rotated in the oppositedirection, or in other words in a direction indicated by the arrow 24.Control means have therefore been pro vided whereby a deflection of thetracer will influence a suitable power means to effect rotation of thetracer head so that for each undeflection or increased deflection of thetracer button, the line Y-Y' will be realigned perpendicular to the newsurface and maintained perpendicular thereto because it should now beobvious that it is only by maintaining this perpendicular rela tionshipthat true reproduction results can be accomplished with a tracer buttonof unequal diameter to the cutter.

If the cutter and tracer head are rotatable about fixed axes, means mustbe provided for eiiecting movement of the work and pattern relative tothese fixed axes in order that the entire pcriphery of the work may befinished. In other words, a relative feeding movement must be providedfor, and if the line Y-Y is maintained perpendicular to the tangent ofthe pattern at the point of contact with the tracer, the feedingmovement will always be in a direction at right angles to this line, orin other words along the line X-X" as respects the pattern and X"-X' asrespects the work. For this reason the line may be utilized throughoutthese diagrams to indicate the direction of food while the line Y-Y willalways point toward the pattern during normal operation of the machineand be perpendicular to the tangent at the point of contact between thepattern and tracer. 7

Since it is thus necessary to continually change the resultant directionof feed in accordance with the pattern, power means have been providedherein under control of the tracer for determining rotation of thetracer head and actuation of a pair of slides relatively movable atright angles to one another whereby they may be moved at such relativevelocities that the desired resultant feed direction will be obtained.The latter may be accomplished by means of a rotatable power controlmember which is so connected to the slides that each anguI-arly adjustedposition thereof will effect a feed movement in a predetermineddirection. This member bears such a relationship to the tracer controlmechanism that the resultant relative movement effected thereby will bein a line parallel to the line X-X.

From the foregoing it will be seen that a new principle of patterncontrolling the position of a which may be of diifercnt diameter thanthe cutter is utilized for scanning the pattern surface, the tracerbutton being eccentrically mounted for bodily rotation about an axislocated intermediate its own center and the point of tangency with thepattern so that a line connecting this axis to the point of tangency maybe maintained substantially perpendicular to a tangent of the pattern atthe point of contact with the tracer button.

Absolutey accurate results; however, cannot be obtained if the center ofthe tracer button is positioned on the ,line Y-Y in alignment with thepoint it, as shown in Figure 18, because an additional deflection isimparted to the tracer upon rotation of the head in addition to thenormal deflection imparted thereto by the pattern itself. The eifectproduced by this rotation is the same as if the radial arm l2-l5 werelengthened and it is this lengthening that causes increased one another.

deflection of the tracer. On account of this, the tracer button cannever return to its neutral position and therefore the feed movementwhich was stopped cannot be reinitiated. It should therefore be obviousthat the tracer button must either be so formed or so positioned thatthis inoperative condition does not occur. It has been overcome in thepresent instance by slightly offsetting the center of the tracer buttonlaterally of the axis Y-Y' as more particularly shown in Figure 16. Inthis figure it will be noted that the center ll of the tracer buttonlies on the axis Y2-Y3 and the center l2 of the tracer head still lieson the axis Y-Y'. The amount of lateral offset is greatly exaggerated inthis figure, but as a matter of fact it is only a few thousandths of aninch. It will also be noted that this lateral offset is on the advanceside of the axis YY' or, in other words, on the side toward which thedirection of feed occurs. Careful observation of Figure 16 will disclosethe fact that when the point I! is rotated in a clockwise directionabout the center |2 that the point I! will actually move through spacein a direction away from the surface of the pattern and therefore theend I5 of the radius |'I--|5 which lies on the axis Y2--Y3 will actuallymove away from the pattern surface. Although the amount of this movementis comparatively small, it is sufficient to correct for the apparentelongation of the radial arm |'l-|5, Figure 18, and produce a situationin which the radial arm will have the same length irrespective ofrotation of the button. Attention is invited to the fact that evenalthough the axis YlE-Yii is laterally displaced with respect to theaxis Ti -Y the power urge of the tracer mechanism toward the 'ttern isstill substantially o the tangent drawn through the i. that the distancebetween a er button when undeflected and the of the tracer head could befixed but it is preferable for reasons set forth herein that they berelatively adjustable with respect to One form that this adjustablemounting might take is illustrated in Figures 6 and 7. As shown, thetracer head 25 is secured to the end of the rotatable member 26 whichhas keyed or otherwise secured to its upper end the operating gear 21. Akey 28 and lock nut 29 may be utilized for securing the parts togetherfor joint rotation. The head 25 is provided with a dove-tail guideway30, the center of which it will be noted intersects the axis of therotatable member 26, as more particularly shown in Figure '7. A tracerbody 3| is slidably mounted in this guideway and has a threaded aperture32 in one end for receiving an adjusting screw 33. This screw is heldagainst axial movement in the member 25 by means of a collar 34 engagingone face of the tracer body and a dial 35 secured to the adjusting screwby a set screw 36. Rotation of the adjusting screw is effected by anoperating knob 37 secured to the outer end thereof, and

the dial cooperates with a fixed mark 38 on the body, the graduationsbeing such as to permit micrometer adjustment of the tracer body.

The lower end of the tracer body has a circular threaded opening 39 inwhich is mounted a reaction ring 40 for supporting a collar buttonshaped member 4| having a depending annular flange 42; The ring 40 hasan upstanding flange 43. the outer surface of which is parallel to theinner surface of the flange 42 and anti-friction members such as theballs 44 may be mounted between the two flanges to insure movementbetween the parts with the least amount of friction.

A button shaped portion 45 member 4| is secured to the end of the shank46 by means of the lock bolt 41. The shank projects from the center ofthe member 4| which thereby positions the tracer button 48 exactly inthe center of the reaction ring 40. A depression 49 is formed in thecenter ofthe top surface of the member 4| for receiving ball 50 whichmakes point contact with a disk attached to the end of the verticallyreciprocable rod or tracer arm 52. This rod is mounted in anti-frictionbearings 53 in the central bore 54 of the rotatable member 24. Thetracer arm 52 is operatively connected at the upper end to a powercontrol mechanism to be described later for controlling the rotation ofthe tracer head and the feed rate of the work relative to the cutter.

The tracer button and its support are so mounted that axial pressure onthe button will effect axial movement of the member 4| which will beaccurately guided by the anti-friction members 44 and it in turn throughthe ball 50 and flange or disk 5| will cause vertical reciprocation ofthe tracer arm 52. Likewise, a radial pressure on the button 48 willcause the member 4| to pivot about a point on its periphery which inturn will cause an elevation of the ball 50 and disk 5| and thereby asimilar axial movement of the tracer arm 52. It will thus be noticedthat either an axial or a radial thrust on the member 45 will result inaxial movement of the tracer arm and thereby actuation of the powercontrol mechanism.

The advantage of this eccentric adjusting mechanism is that it permitsthe distance between the center of the tracer head and the axis of thetracer button 48 to be varied relative to one another so-that if thediameter of the cutter is changed either by the use of a new cutter ordue to the fact that the present cutter has been slightly reduced indiameter due to sharpening or grinding thereof, the tracer button may bere-adjusted to insure that the distance from the center of the tracerhead to the pattern contacting surface of the button is equal to theradius of the cutter. It also permits this surface of the button to bepositioned at a distance which is slightly greater or less than theradius of the cutter so a slight amount of stock may be left on the workfor subsequent finishing operations over the true size of the pattern.

Another important use of this adjusting mechanism, however, is in theproduction of punches and dies and especially where it is desired to cuta punch from the pattern of the die with which it is to be used, or viceversa. In such a case, it is only necessary to provide one pattern fromwhich both a duplicate and its counterpart may be formed constitutingfor instance a punch and corresponding female die member. In making thisadjustment, provision may also be made for whatever clearance is desiredbetween the two parts when they are in use such as in metal formingoperations.

Due to the unique construction of the tracer mechanism the tracer buttonitself may be given various shapes. Ordinarily, these heads would becircular because they are the easiest to manufacture although certainadvantages arise from using the semicircular shapes, shown in Figure 19.The tracer heads should have an arcuate surface however, of at least anangle of 90 degrees and preferably slightly more in order to insureproper reproduction of internal corners.

For instance, as shown in Figure 20, when the tracer button indicated bythe reference numeral 55 traveling in the direction of the arrow 55contacts the side wall 51 of a pattern the cutter 58, which has beensuperimposed hereon to show the relative relation between the movementof the tracer and cutter, if larger than the tracer but- 51 before thetracer can come into action to'checlb ton 55, will overrun beyond theintended surface itsmovement. While if a cutter such as 51 and smallerthan the tracer is used it will be apparent that the periphery of thetracer will engage the wall before the cutter engages the correspondingwall'on the work. If the tracer is intended to have an initialdeflection before reaching an operating position, such as the distance59 in Figure 20,,it will be apparent that the tracer button should havea radius at least this much greater than the butter in order to insurethat this initial deflection may take place before the cutter engagesthe work. It will therefore be seen that for many types of work it willbe neecssary to have the tracer button larger than the diameter of thecutter by the amount set forth. If the type of work is comparativelyflat or convex, this may not be necessary and cutters larger in diameterthan the tracer button may be utilized.

Having chosen a suitable type of tracer button, it is secured to the endof the tracer mechanism by screwing the threaded end 41 of the tracer ina threaded socket formed in the end of member iii) ' ing' the machine.

II and it is now ready to establish contact with the pattern. Aspreviously mentioned, this contact is established automatically, theoperator inerely positioning the tracer head so that the line X-X pointstoward the pattern and start- The manner in which this contact isautomatically established is illustrated diagrammatically in Figures 10to 16 inclusive. The manner of establishing contact is the same-irrespective of the relative position of the tracer button with respectto the axis of the tracer head and generally irrespective of the type oftracer button utilized. I

Attention is invited to the fact, at this point, that the power meanscontrolled by the tracer mechanism for effecting rotation of the tracerhead and the feeding of the work is so arranged that during increase intracer deflection, the rate of rotation of the tracer head will decreasefrom a maximum to zero, while at the same time the feed rate will beincreased from zero to maximum. This condition will exist between acer-. tain minimum tracer deflection and a predetermined intermediateamount of tracer deflection, the last named position being termed hereinthe neutral position. At this position the feed rate will be a maximumand the rate of rotation of the tracer head will be zero. Furtherdeflection of the tracer beyond this point to a position herein termedthe safety position will find the feed rate decreased from a maximum toZero and the rate of rotation of the tracer head increased from zero tomaximum. Further deflection oi the tracer beyond the safety positionwill effect no change, that is, the feed rate will still remain at zerowhile the tracer will be rotating at its maximum rate. Attention is alsoinvited to the fact that at the neutral position when the rate ofrotation of-the tracer head passes through zero, its direction ofrotation changes upon subsequent increase in rate.

When the tracer button is free of the pattern, the power control meanswill be so positioned that when the machine is started the feed ratewill be at a maximum and the power ,willbe disconnected from the tracerhead. As previously explained in connection with Figure 18, theaxia X-Xindicates the direction of relative f movement between the pattern andtracer as well as'between the cutter and work and the axis Y-Y' willpoint toward the pattern when in a normal operating position. Since itis necessary first to efiectcontact between the pattern and tracer, thetracer head will be positioned so that the axis X-X' points toward thepattern as shown in Figure 10 so when the machine is started the tracerwill approach the pattern. ure 10 the reference numeral l8 indicates thetracer button while the intersection of the rectangular coordinate axesis indicated by the reference numeral H which intersection is also thecenter of rotation of the tracer head. For the purpose of convenience inillustration, the cutter i3 is superimposed on the diagram, its axisalso lying at the point I? in order to show more conveniently therelative position of the tracer and cutter with respect to the patternand work. The center of thetracer button when in a free position isindicated by the point H.

After the machine is started the maximum feed rate will continue untilthe tracer i3 contacts the pattern at the point l as shown in Figure 10.Continued movement in the direction X will cause the tracer button to bedeflected from its free position to the position id as shown in Figure11, the amount of this deflection being represented by the distance 60.This distance has been greatly exaggerated for the purpose ofexplanation, but as a practical matter it is only a few thousandths ofan inch. After this first deflection which will be a predeterminedamount the tracer will rach the engagement position, at which time thetracer arm will have influenced the power means in such a way that thefeed rate is immediately reduced to zero, and the rotation of the tracerhead in onedirection is immediately established at a maximum rate. If itis intended to scan the pattern in a direction indicated by the arrow[Si in Figure 10, it will be evident from the description of Figure 18that the axis XX' must be readjusted parallel to the arrow Si in orderthat feed movement will progress in that direction.

The power means will therefore be connected to the tracer head to causerotation thereof in a counter-clockwise direction. Rotation in thisdirection will actually cause relative movement or deflection of thetracer button in the opposite direction and the point 19 will movefurther away from the point I 1 indicating further deflection of thetracer, even although the feed rate is substantially at zero. Thisfurther deflection of the tracer will so influence the power means as tocause an increase or acceleration in the feed rate and a deceleration inthe rate of rota-- tion of the tracer head. The result of these twomovements, however, will be a further de flection of the tracer to aneutral position which is indicated in Figure 12. This will so affectthe power control means that the feed rate will be increased to amaximum and the rotation of the tracer will be decreased to zero.

Since the feed rate is continuing, further deflection of the tracer willfollow and as the neutral position is reached and passed, the rotationof the tracer head will begin to accelerate, but in a reverse directionas indicated by the arrow 62 in Figure 13. In this condition the feedrate will be decreasing and the rate of rotation of the tracer will beincreasing, one tending to cause undeflection of the tracer and theother tending to increase the deflection of the tracer and each forcewill thus alternately prevail over the other until a position such asshown in Figure 15 has been reached. In other words, there are twoagencies taking place at the same time, one tending to increase and theother tending to decrease the tracer deflection. A condition ofequilibrium will therefore be brought about made up of a combination ofthese two agencies.

The resultant movement will consist partially of feed rate and partiallyof clockwise rotation and the point 12 will therefore approach themaster more and more obliquely and the parts will pass through thesuccessive positions indicated by'Figures 14 and 15 until the line X-X'becomes substantially parallel to the surface of the pattern asindicated in Figure 16. At this point if the rotation were to continue,then the resultant feed movement would bring about a decrease in thedeflection of the tracer button because its direction would be divergentwith respect to the pattern. Such a decrease in deflection would,however, tend to decrease the rate of rotation of the tracer to zero andincrease the feed rate, the tracer returning to the neutral position.Once the tracer is in the neutral position if the profile is straight,the feed rate will be at its maximum and the tracer head will bestationary. From this position on, the action will be the same as thatdescribed in connection with Figure 18.

From this it will be seen that the tracer will move into engagement withthe pattern and automatically position the cutter in contact with thework 'without over-running and without attention on the part of theoperator. The power means utilized to effect rotation of the tracer headand the feeding of the work will now be described. This power means aswell as the corn trol means therefore may be of any suitable type, suchas electric, hydraulicor mechanical. A Inachine embodying one form, suchas hydraulic, is shown herein which may be structurally composed asfollows:

An upright column 63 is provided which has guideways 64 formed on itsfront face for supporting a vertically movable knee structure 65. Theknee has a horizontal guideway 66 formed on its upper face forsupporting a saddle 6'! which is movable in a horizontal plane towardand from the column for supporting a table 68 for movement transverselythereof. The table is, in this instance, adapted to support the work andpattern in cooperative relation to a cutter 69 and a tracer 48 supportedon the over-hanging arm ll formed integral with the top of the column63. Since the cutter and tracer are substantially sta tionary, the threemovements necessary for die- Sinking: and profiling purposes areimparted to the work and pattern, although it will be apparent that oneor more of these movements may be imparted to the tracer and cutter andis so included within the scope of this invention.

shown extends from the shaft 13 to a pair of bevel gears '14 journaledin the head H for r0- tating the spindle and cutter at selective speeds.This variable speed transmission is adapted to be aoo sca connected tothe shaft 13 by a clutch member l5 operated by a manual control lever"i6 journaled on the side of the column as shown in Figure 1. A verticalsplined shaft 17 is journaled in the side of the column and operativelyconnectedto the prime mover through clutch 15. This shaft extendsdownward, through a bracket 18 projecting from the rear of the knee, andcontinues into the pedestal 19 of the column for actuating a centrifugalpump which may be used to supply coolant to the cutter.

The bracket 18 contains a pair of bevel gears 80, one of which issplined to shaft 11 for driving a horizontal shaft 8i which isoperatively con.- nected to the pump 82. This pump supplies fluid underpressure for operation of the hydraulically actuated mechanism utilizedfor feeding the work and rotating the tracer head. This pump may be ofthe constant displacement type, in which case a double throttle feedcontrol valve is associated therewith to vary the feed rate, or it maybe a variable displacement pump, the feed rate then being varieddirectly by varying the delivery of the pump.

The pump 82 has an intake pipe 83 through which fluid is withdrawn froma reservoir 84 located in the bottom of the knee for delivery throughpipe 85 to the pressure port 86 located in the double throttle valveindicated generally by the reference numeral 81 in Figure 17. Thepressure port 86 is considerably wider than the spool 88 of the valveplunger 89 whereby fluid entering the valve will be divided by thespool, a portion flowing through distributor port 9i and the remainderdischarging through distributor port 90. The spool 88 is cylindrical inform and the opposite ends 92 and 93 are tapered to form initialhydraulic resistances at the port 86. If the hydraulic resistances areequal, the flow will be equally divided. The plunger 89 may belongitudinally adjusted in the valve housing as by means of the cam 94'on lever 94 pivotally mounted-at 95 on the front part of the' machine asshown in Figures 1 and 2, and a clasp lever Q5 is provided for holdingthe cam and thereby the valve in any adjusted position.

A balancing valve 96 is associated with the double throttle valve tomaintain the division of flow as determined by the position of the valvespool 88 as more fully explained in copending application of Ernst andSassen, Serial Number 490,154, filed October 21, 1930.

The port is connected by channel 97 to the end 98 of the balancing valvewhich has a tapered reciprocable plunger 99. The other port 91 isconnected to the opposite end of the balancing valve through a hydraulicresistance I06 which may be a coil of copper tubing so that fluidpressure will act on the end of the plunger 99 to urge the same in aposition to close the port it'll. As this port closes, the pressurerises in the end 98 of the balancing valve and will continue to riseuntil the pressure in both ends are equal. This will insure that thepressures at ports 90 and 9! are equal and if the pressures are equal,then the division of flow will be in accordance to that established bythe setting of the throttle valve.

A branch line N32 is also connected to the end 98 of the balancing valvefor supplyinga small amount of pressure fluid to the end 103 of thedouble throttle valve to thereby maintain the same in contact with thecam 94 of the adjusting lever. The double throttle valve functions todetermine the feed rate of the movable slides lilt ll

a sence of the machine and is therefore constructed in the manner setforth to divert part of the fluid from the pump M to reservoir in orderto reduce the flow to the slides. The port lfil has channel lll lconnected thereto for conducting the diverted fluid to the reservoir tl.

An emergency relief valve W5 is interposed between the incoming line 85and the return line lllt whereby the valve will open against thecompression of spring lllt to relieve excessive high pressure in thesystem and prevent damage thereto.

The fluid utilized for power purposes is conducted from port Ell througha channel l9? to the power control element which in this case is in theform of a distributor valve I08, Figures 1'7, 22, 23 and 24.- This valveis provided with pressure ports Hi9 and llll to which the line Hill isconnected. This valve has reciprocably mounted therein a plunger l llwhich is operatively coupled to the tracer arm 52 previously describedwhereby deflection of the tracer will effect reciprocation of theplunger. A spring M2 is mounted in the upper end of the valve housingfor maintaining the plunger in a downward position and in turn tendingto maintain the tracer button in a vertical or undeflected position.

This valve is provided with additional ports lllll, ll l and M5, theport ll3 being connected by line l26 to the end N6 of balancing valvelll having valve plunger lit; the port ll l being connected by line ltlto the end llll of the valve l l'l and also the end lQfl of balancingvalve llll having reciprocable plunger lit; and the port llll beingconnected by line ltd to the end its of balancing valve ltl havingreciprocable plungltlll ll ll till er l25 mounted therein. The port llland connected line lllii'is utilized normally to supply the operatingfluid to effect actuation of .the work supporting slides and therebyeffect the feed movement; while the ports ll l and llfl are utilized forsupplying fluid to the hydraulic motor ltll, more particularly shown inFigure 8, for effecting rotation of the tracer head.

When the valve plunger lll is in a position corresponding to the freeposition of the tracer button, the spool ltd will close the port lllthereby preventing fluid entering pressure port ltd, which is slightlyopen by spool ltl, from flowing to channel llli, but the annular grooveltt of this port still permits a flow through hydraulic resistance litunafiected by the position of spool ldl. This flow is of the nature of aslight leakage into line ltb in order to maintain a nominal pressuretherein, there also being a slight leakage out of this line throughhydraulic resistance lll. These hydraulic resistances, which may be inthe form of small copper tubing, cause a certain pressure drop to occuracross each one thereby maintaining a high pressure in the line MW and anominal pressure in line l26. The spool llll' is in such a position thatthe port llt will be coupled to port l ll permitting pressure flow toline lll which, after passing to the end lZll of valve ltl and throughthe end N9 of balancing valve lll, will be connected by channel ltli toport lilfi of the balancing valve ll'l. The pressure at l l9 acting onthe end of valve ll'l will shift the plunger to the right as shown inFigure 17 thereby coupling the port lit to port ltl through which thefluid will continue to port lid of the directional control valve llfl bymeans of channel ltd effecting actuation of the slides in a manner to beexplained hereafter. The valve l ll has a pair of additional poms l lland llll! which are connected respectively by channels l lll and lll toports lit and l lb of the reversing valve l l'l of the hydraulic motor.

Eachof these balancing valves is mounted in a separate sleeve, thesleeves being mounted in a common valve housing and each sleeve isseparated by means of the construction shown in Figure 21. As thereshown, a thin plate 235 is inserted between the end of valve sleeves 205and 29'! and a port 238 is formed in the valve housing such as 2539, theport being of sufficient width to communicate with the grooves 2 ill and2l l formed in the end of the opposed sleeves, the ends of these sleevesalso having radial grooves such as 2l2 which permit the fluid to flowfrom the annular grooves to the interior of the sleeve to admit orexhaust fluid from the ends of the respective valves. If fluid isadmitted through a port such as 2th, equal pressure will be exerted onboth ends of the respective valves tending to shift the same in oppositedirections, while if the port MB is connected to exhaust, the respectivepistons will move in the opposite directions when pressure is exertedupon the opposite ends of either or both.

The shifting of valve spool lit to the left upon the admission ofpressure to the end lllll of the cylinder l2l due to flow in line Illwill cause the fluid in the opposite end of the cylinder to be forcedout due to the lower pressure in line H25; and this fluid will be forcedinto the forward end of cylinder lhl thereby shifting the spool I25thereof to the left. It will thus be seen that in the free position ofthe tracer that all the fluid will be delivered to channel l 38 toeffect feed movement of the slides at the maximum rate. The flow fromline l2'l to channel ltd to effect this feed movement only occurs whenthe tracer is in a free positon, as in all other positions the how inchannel ll'l is utilized as before described to effect operation of thetracer head motor.

Upon relative approach between pattern and tracer to establish contact,the feed movement will continue until the tracer has been deflected tothe engagement position previously mentioned. This will cause upwardmovement of the plunger lllt to the position shown in Figure 22 and fromthat figure it will be noticed that the spool l3!) has been moved upwardto a position such that the port l l3 has opened just the slightestamount to permit a slight flow therethrough. Also that the spool ltl'has moved upward to close almost the port lll and thus stop the flow tochannel lt'l. As soon as fluid begins to flow through port l l3 andchannel lit, pressure will buildup in the end llt of valve ll'l shiftingthe plunger lld thereof all the way to the left.

The moment this plunger shifts, port lt'l will be disconnected from portltfi, and connected to channel lift which will then supply the fluid tothe work supporting slides. Although this flow through port lit at thebeginning is a limited flow, it will be seen that the work slides havebeen suddently disconnected from a full flow at maximum rate to a smallflow corresponding to a minimum rate. At the same time the shifting ofplunger l l8 to the left couples port l36 to port l l2, fluid flowingthrough channel lit to cause rotation of the tracer head at its maximumrate. Since fluid is being supplied to the tracer head motor throughchannel l l l, the opposite channel M3 will be connected to reservoirthrough coupling of ports lll and HM, and since the valve spool ltl isstill in a left hand position, the

channel I 28 "will be connected by means of the rate of rotation of thetracer head. This condltion will continue until the valve reaches theposition shown in Figure 23 at which time the ports I09 and I I3 will beopened an equal amount permitting a maximum flow to the operatingslides, and the spool I3I' will be in a position exactly central of portI I0. Since the spool and the annular groove of this port are the samewidth the port will be substantially closed and any leakage will be thesame on either side there-- of which will not eiiect movement of therotary head. This position is known as the neutral position and it willnow be noted that a slight shifting of the valve plunger I08 in eitherdirection from this position will connect the port IIO with either portH4 or II5 to cause rotation of the tracer head in one direction or theother, accompanied by a decrease in the feed rate.

In Figure 24 the valve is shown in its extreme upward positioncorresponding to maximum defiection of the tracer, and it will be notedfrom this figure that the port H0 is connected to the port I I5 whichwill now cause a greater pressure in the end I23 of valve I25 than inthe opposite end, thereby connecting the channel I21 to the branchreturn line I21 permitting the motor to exhaust through channel I44while the line I26 will be connected through ports I4! and MI to channelI43 thus causing reverse rotation of the tracer head. It will be notedthat when fluid is supplied to the tracer head motor through either oneof channels I44 or I43, that the other channel is connected to reservoirthru the respective balancing valves I22 and I25. For instance, whenfluid is supplied to channel I44, the return flow passes throughbalancing valve I22,

one end of this valve being subjected to the pressure of the feed lineI26 and the opposite end being subjected to the forward pressure of thetracer head motor. Since the work resistance of the tracer head motor isvery low compared to the work resistance of the operating slides, thebalancing valve will take up a position almost closing the port to thebranch return line thereby building up an additional work resistancewhich will be reflected in the pressure existing at-the end I20 of thevalve and causing this pressure to balance the pressure on the oppositeend. The valve will assume a floating condition during actual operationof the machine. When the forward pressure is in channel I43, then thisbalancing effect is assumed by plunger I25 which in turn will balancethe pressure in line I28 against the feed pressure in line I26 andmaintain these pr; sures equal irrespective of variations in the workresistances. From the foregoing it should now be apparent that a powermeans has been .w ided under the control of the tracer for 3: citingautomatic rotation of the tracer head and the distribution of power tothe various work slides.

The construction and manner of operation of the tracer head motor willnow be described.

As shown in Figure 8, the ports I45 and I46 are formed in the motorcasting I46 and communicate with annular grooves I49 and I50 formed inthe periphery of a sleeve I5I rotatably journaled at opposite ends inbearings I52 and I53. A rotatably adjustable valve member I54 is mountedin the sleeve RH for independent movement and has a port I55 formedtherein communicating with a longitudinal pressure groove I56 and anadditional port I51 communicating with the longitudinal groove I58. Thegrooves I56 and I58 communicate with lateral grooves I60 and I6I, Figure9, formed in the sleeve I5I, there being an intermediate portion I62constituting a pintle which determines the flow to the three channelsI63, I64 and I65 leading respectively to the motor cylinders I66, I61and I68. The rotatable member I54 projects beyond the end of sleeve ISIfor the purpose of attaching an operating knob I58. A spring presseddetent I59 serves to hold the valve member in a given rotatable positionrelative to the pintle and also serves to connect the valve to thesleeve for rotation therewith. From Figure 9 it should now be apparentthat if the valve member I54 is rotated through I80 degrees that thegrooves I55 and IE8 will be reversely connected to opposite sidesof thepintle. This valve thus serves as a reversing valve, in the sense thatit determines in the first instance the direction of rotation that willbe imparted to the tracer head, the plunger I08 merely changing thisdirection.

Reciprocably mounted in each cylinder is a piston I69 engaging aneccentric cam I10 having an anti-friction ring Ill mounted on itsperiphery to eliminate wear between the surface of the cam and thepiston. The cams I10 are keyed or splined on a drive shaft I12 which isintegrally connected to the sleeve I5I, the sleeve having a spiral gearI13 secured thereto. This gear meshes with a similar gear I14 keyed tothe shaft I15 which in turn efi'ects rotation of the tracer head. Itwill thus be seen that power means in the form of an hydraulic motorhave been provided for effecting rotation of the tracer head uponinitial deflection of the tracer, and for changing this direction afterthe tracer has reached its neutral position. This shaft also serves toeffect rotational movement of the di rectional control valve I40.

The directional control valve is provided with four ports I1u, I11, I18and I19 reference being had more particularly to Figures 17 and 25 to 29inclusive which are connected respectively by lines I80, I8I, I82 andI83 to a series of ports in a plurality of balancing valves indicatedgenerally by the reference numerals I84, I85, I86 and Each of thesechannels are also connected respectively to an end of the hydraulicmotors for effecting movement of the work in two directions in a givenplane. For instance assuming that the motors are oriented in such amanner in Figure 17 that they effect movement in the direc tion of thefour poles of the compass as shown in Figure 17A, then the ends of therespective cylinders to which pressure is applied to effect movement ina given direction may be denoted by a suitable indicia according to thedirection of movement effected. For instance, if movement of piston I88reciprocably mounted in cylinder I89 effects movement in a northdirection when pressure is admitted to the port I90 thereof then thisend of the cylinder and its supply line may be designated by thereference numeral N. If pressure is admitted to port IQ! of cylinderI89, movement will be effected in a south direction and this end of thecylinder and its supply line may be designated by the letter S.Similarly, the opposite ends of cylinder I92 and the respective supplylines I82 and I89 may be designated E and W. When pressure is admittedto any one of the four motor ports I99, I9I, I93 or I99, movement in thedirection of one of the four points of the compass will result and theopposite end of the particular cylinder which is being operated will beconnected to exhaust, while the piston in the other motor cylinder willbe hydraulically locked to prevent relative movement thereof. Ifmovement is to be effected in any direction intervmediate these fourcardinal positions, pressure must be admitted to at least two of theports I99, I9I, I93 and I99 but the two ports must be in differentcylinders. If pressure is admitted to two cylinders at the same time,there must be a proportionatedivision of flow between them which willalways be uneven, except for a 45 degree movement, thereby impartingunequal velocities to the slides and in order to maintain thesevelocities it is necessary to balance the flow to these cylinders inorder to maintain their respective velocities regardless of variationsin work resist- Since there are four combinations possible, fourbalancing valves have beenprovided, the valve I84 balancing the flowbetween south and east lines, valve I95 balancing the flow between theeast and north lines, valve I86 balancing the flow between the north andwest lines and valve I81 balancing the west and south lines. The mannerof operation is as follows:

If pressure is supplied t the line I99 to cheat movement in a southdirec ion, the opposite end of cylinder I99 will be connected toreservoir through the balancing valves as explained hereafter and theremaining ports H9 and N9 of the directional control valve will beclosed, permitting no flow in lines I9I, I92 and I89. Pressure fluid inline I99 will flow to port I95 of balancing valve I99 which will shiftthe plunger thereof upward as viewed in Figure 17 and connect port I96to which return line 2I6 from port I99 of cylinder I89 is connected,with port I91. Pressure in line I99 will also connect with port 299 ofvalve I9I thereby shifting the plunger thereof downward connecting port29! with port 292. This couples channel 2I'I extending between ports I9land NI to the return line 229 thus permitting discharge from the northend of cylinder I99.

Since the lines I9I and 2I9 are connected to exhaust, the port 2I9 willconnect the adjacent ends of valves I99 and I99 to reservoir therebypermitting the pressure at ports I99 and 299 to force the fluid from theopposite ends of these valves I94 and I9! through ports 2I9 and 2I5 .tothe ends of valves I99 and I99 to cause their plungers to move towardone another. In a similar manner if pressure is admitted to line I9I toeffect movement of the table in a north direction, the channel I89 wouldbe connected to exhaust, pressure being admitted to port 2I9 effectingseparation of the plungers in valves I99 and I89 and this would bepossible because the ports I95 and 299 will be connected to reservoirthrough ports 299 and 299, channel 299, ports 297i and 299, and channel229. Likewise if pressure is admitted to either line I92 or I99, thecorresponding line will be connected to reservoir.

If pressure is admitted to two lines to effect movement in an angulardirection such as southwest, fluid will then be admitted to channels I99and I89 and the corresponding channels I92 and I9I will be sealed fromthe incoming pressure. It is therefore necessary to balance the pressurein lines I99 and I99 to maintain whatever volumetric proportions areestablished by the directional control valve I99 irrespective ofvariations in work resistance. In this case fluid will be admitted toport 2I9 tending to shift the plunger of balancing valve I82 upwardwhile pressure will be admitted to the port 299 tending to shift thesame plunger downward. It will thus be seen that the plunger of valveI92 will take up a position that will balance the pressure between thesouth and west lines and maintain the proportionate flows thereto. Thereturn ilow from port I99 will pass through channel 2I9, port I99,through valve I99, port I99, and channel 2II to port 29I, which will nowbe partially connected to port 292 by the annular groove 2 I9 of valveplunger I9I. Similarly, the exhaust from port I99 of cylinder I92 willpass through channel 2I9 to port 299 which will be partially connectedto port 299 by the annular groove 229 02 valve spool I917. The exhaustfluid will flow irom this port through channel 22I, port 222, annulargroove 229 oi valve I99 and port 229 to the main return line 229. Fromthis it will be seen that as the valve I9'I floats baclr and forth, thespool 229 will vary the openings of ports 292 and thereby varying-thehydraulic resistance thereof and controlling the return flow from thetwo cyl-= inders to balance the incoming pressures to those cylindersirrespective of variations in work resistance. explained in copendingapplication 'of Hans Ernst, Serial Number 614,980, filed June 2, i932.Simi larly the valve I99 will balance the pressure distribution to portsI99 and I99 when the movement is in the northwest quadrant; the valveI99 will balance the pressure between ports I99 and I99 when themovement is in the northeast quadrant; and the valve I99 will balancethe pressure between port I99 and port I9I when the movement is in thesoutheast quadrant. It will thus be seen that balancing valves have beenprovided for maintaining the division of flow to the respectivecylinders to maintain the rate of movement in the various angulardirections at the velocities determined by the directional control valveand irrespective of variations in the work resistances encountered inany of these directions.

The construction of the hydraulic motors that effect actuation of thesaddle and table is more particularly shown in Figures 3, a and 5. InFigure l, which shows the construction of the saddle motor, it will beseen that the supply lines I99 and I9I comprise channels formed in theknee casting which communicates with radial channels 222 and 229 formedin a piston rod 229 which is fixed in the knee 99 and held againstlongitudinal movement by a washer 299 engaging a shoulder 29I formed onthe piston rod, and a lock nut 292 threaded on the extreme end of thepiston rod and bearing against a second washer 299, rotation of the nutdrawing the wash-- ers into engagement with opposite sides of a fixedpart of the knee. The other end of the piston rod is supported instuffing boxes 299 formed at opposite ends of the cylinder I99 which inturn depends from the underside of the saclile. In other words, one endof the piston is supported by the knee and the other end by the cylinderheads of the saddle actuating motor. A piston I99 is integrally securedto the end of the piston rod and held against longitudinal move-- menttherewith so that in operation the cylinder constitutes the movingmember. A longitudinal This is in accordance with the theory O wil bore235 is formed in the piston rod and connected at one end by port 228 tothe supply line HM and at the other end by a radial bore 236 to the leftend of the cylinder I89 as viewed in Figure 4. A tube 23? of smallerdiameter than the bore 235 is mounted therein and connected at one endby the radial bore 221 to the supply line Hi0 and at the opposite end bya radial bore 238 to the right hand end of cylinder I89. It will thus beseen that the alternate admission of pressure to channels I80 and I9Iwill cause movement of the work and pattern in one direction relative tothe cutter and tracer.

The fluid conducting channels I82 and I83 are also formed in the kneecasting only one of which is shown in Figure 5, and terminate inthreaded bores 239 in which is fastened one end of a tube 240 formingpart of a telescoping tube construction whereby connection is maintainedwith the saddle 61 during reciprocation thereof. A longitudinal bore MIis formed in the saddle, the opposite ends of the bore having stuffingboxes 242 mounted therein through which the tube 24!] slides. The tube240 has a radial bore 244 communicating with the interior of the bore24! whereby fluid from channel I82 will be conducted to the bore in thesaddle in all positions of longitudinal adjustment thereof. A verticalbore 245 intersects the bore I and has threaded therein a pipe 246 whichleads to one end of the table cylinder, such as port I93. The tablecylinder I92, as shown in Figure 3, is supported at opposite ends on thesaddle 6'! and fixed therewith against 1ongitudinal movement. A pistonrod 241 is fixed at one end to the depending apron 248 of the table andsupported at the other end by the bracket 249 attached to the oppositeend of the table. A piston 25B is formed integral with the piston rodwhereby upon admission of pressure to the cylinder the piston, pistonrod and table will move relatively to the fixed cylinder I92. Theconstruction shown in Figure 5 is duplicated for connecting the othertable channel I83 with the port I94. From this it will be seen that evenalthough the saddle is slidably mounted on the knee that a flexibleconnection is maintained for supplying fluid to the table in allpositions thereof.

The construction of the directional control valve which divides the flowamong the four supply lines of the slide actuating motors in suchsequence that one rotation of the valve will efl'ect relative movementof the work support about the tracer through an angle of 360 degreeswill now be described, reference being had more particularly to Figures25 to 29 inclusive. The supply line I38 is connected to the port I39formed in the housing I40 and this port communicates with an annulargroove 25I formed in the sleeve 252 which is fixed in the housingagainst rotation. A plurality of radial bores 253 are formed in thebottom of the annular groove to conduct the fluid to a second annulargroove 254 formed in the rotatable shaft 25. An axial bore 255 is formedin the member 26 for conducting the pressure from the annular groove 254to a plurality of S"lll(3lll&1 slots 256, 251, 258 and 259 formed in themember 26, each of these slots serving to supply pressure to aparticular motor supply line. As shown in Figure 26, the slot 255 isadapted to supply line I83; the slot 251 in Figure 27 is utilized tosupply channel I82; slot 258 as shown in Figure 28 is utilized to supplychannel ISI, and the slot 259 as shown in Figure 29 is utilized tosupply channel I80. The sleeve 252 also has a plurality of segmentalgrooves 256, 251', 258 and 259 formed therein, these grooves beinglongitudinally spaced oi the sleeve so as to register successively withthe channels I83, I82, I8l and I and furthermore these grooves arecircumferentially spaced throughangles of degrees to effect successiveregistration. The segmental slots in the sleeve are so formed that theintersection points 299 and 300 between the slot and the internal boreof the sleeve, Figure 26, subtend an angle of 90 degrees. Similarly, thesegmental groove such as 256 in the rotatable shaft 26 is cut ofsuflicient depth that the chord thereof will be equal to the chordconnecting the points 299 and 350. Thus for each 90 degrees of rotationof member 26, a segmental groove in one member will register with asegmental groove in the sleeve to cause a flow of pressure to aconnected channel, the remaining channels being disconnected frompressure as shown in Figures 26, 27 and 28. The grooves in the member 28are displaced axially with respect to those in the sleeve so as to forma narrow slit as shown in. Figure 30. These slits have suiiicientresistance that the proportion of their openings determines the divisionof flow between the two connected motor passages. From this it should beapparent that if the member 26 is now rotated from the position shown inFigure 29, in a clockwise direction, that the fluid will be successivelysupplied to channels I83, I82, and I8I in the order recited, and thatexcept for the four quadrant positions there will be two of thesechannels connected to pressure simultaneously. For instance, as thevalve rotates clockwise from the position shown in Figures 26 and 29, itwill be apparent that fluid from groove 256 will begin to flow tochannel I83 and that the groove 259 will begin to close off the flow tochannel I'IG. In other words, the length of the slit 2E0 outlined inFigure 30, gradually reduces as shown at 2BI', Figure 31, and increasesas shown at 260 in Figure 32, which is a view looking in the directionof the arrow 3M of Figure 26. Thus as the flow to one is decreased, theflow to the other will be increased because there is a constant incomingflow of fluid which must be divided between these two channels, andinversely as the ratio between the resistances of their respective slitports, the division being maintained irrespective of variations in workresistances by balancing valves which automatically maintain a constantpressure drop across these various resistances or slits at all times.

The rotatable member 26 of the directional control valve is integrallyassociated with the tracer head for joint rotation therewith aspreviously described in connection with Figure 6. As mentioned above, itis desirable that the angular position of the tracer head indicate thedirection of resultant feed movement between the cutter and work as wellas between the tracer and pattern, and in order to bring this about itis evident that during a uniform change or rotation of the tracer head,the resultant direction of feed movement must uniformly change therewithin order that a dial associated with the tracer head will truly indicatethe direction of feed movement. The valve ports shown in Figures 26 to29 inclusive open and close in accordance with the roation of the tracerhead. To insure that the proper quantity of fluid is delivered to therespective operating cylinders in such proportion that the desiredresults may be obiained, the slit openings are somewhat tapered ineiiect at one end as shown so that their area will increasenon-uniformly at the beginning so that the flow will vary lli donated lliii slightly from a straight line and in accordance with the graph shownin Figure 33. In this graph, the angle of rotation of the valve isplotted against quantity of fiuid passing through the ports formed inthis manner it is possible to insure that the fluid will flowtherethrough in a manner to cause the change in the direction of feedmovement in direct relation to the angle of rotation of the tracer head.

To assist the operator in determining the direction of feed movementsuitable indicia have been provided on the tracer head 25 andcorresponding marks on the tracer head support in the manner shown moreparticularly in the expanded view of Figure 34. A fixed mark 260 isplaced on the.

valve housing Mil in a suitable position that it may be viewed by theoperator when standing at his normal position at the front of themachine. Graduation marks extending up to 90 degrees on either side ofthe zero mark may be provided, the graduations to the right of the zeromark indicating the angular movement to the right and the graduations onthe opposite side indicating the angular movement to the left. Aplurality of marks fliil, 262, 263 and 2M are placed on the rotatablehead 25, the mark itl indicating the forward position which when alignedwith the zero mark will indicate that the slide will move in a directiontoward the operator. The words Right and Left may be suitably positionedon opposite sides of the zero mark to indicate the direction in whichthe direction of feed will veer upon movement of the pointer ilil toeither side of the zero point. The pointers 252 and on opposite sides ofpointer filil may be labeled Right" and Left. When either of these marksare aligned with the zero mark, it will indicate that the feed movementwill occur in a direction either to the right or left of the operatorand variation of this mark to either side of the zero line will indicatethat this movement will be either forward or back. The last mark fiii lmay be marked Backward to indicate that the slide will move away fromthe operator. From this it will be seen that the operator may readilyobserve the direction of resultant movement that the slides will takefor any position or the rotatable tracer head.

As previously shown in connection with the operation of the tracer headmotor, the chan nels Hi3 and Hi l are connected together by valveplunger lit as shown in Figure 17 when the tracer is in an undeflectedposition. With these lines connected together, it is apparent that themotor could be manually rotated without difficul ty, because the fluidwill merely flow back and forth from one side of the motor to the other.Due to this condition, it is possible to place a hand wheel 265 on theend of the shaft ltl to eiifect rotation thereof manually so that thetracer head may be rotatably positioned when the power is disconnectedfrom the motor. This is of value when setting up the machine as it isnecessary for the operator to position the tracer head in a properdirection before starting the machine to insure that the tracer willfeed toward the pattern when the machine is started. This arrangement isalso useful when it is desired to do manual profiling without the use ofa pattern where the direction of movement of the cutter is determined bythe operator. In other words the directional control valve is manuallycontrolled rather than pattern controlled.

The operation of the machine for automatic pattern control milling willnow be described.

(Md-Li The pattern and work are positioned on the tahle lid and spacedapart in accordance with the spacing of the axes of the tracer head andcutter. A suitable cutter and tracer are attached to the end of thecutter spindle and tracer arm and the tracer head is positioned so thatthe direction of feed will first be toward the pattern.

then moved to effect engagement 9f clutch l and thereby rotation of thecutter and actuation of the pump M. Fluid pressure will then flow to thetracer head motor and to the table cylinders in such a manner that thetracer will beg-moved into contact with the pattern after which it willreadjust itself parallel to the pattern surface in the manner explainedin detail herein.

After completion of the work, means have been provided for causing thetracer and cutter to move out of contact with the respective elements inan easy and gradual manner to prevent marring of the work. For thispurpose a pivoted handle tliit is mounted on the forward part oi thecolumn and operatively connected to the distributor valve plunger II ll. set screw may he threaded in the end of the lever to limit the amountof movement thereol. Actuation oi this lever against the pressure ofspring lit will move the distributor valve ill toward the safetyposition previously described, which position of the valve will causerotation of the tracer head at a maximum rate and in a direction tocause undefiection of the tracer and at the same time.

reduce the feed rate to a minimum. The lever is held in this positionuntil the tracer head has rotated to such a position that it indicatesmovement of the tracer in a direction away from the pattern whichinsures that the tracer button has left the pattern so that upon releaseof the handle the tracer button will no longer contact the pattern or beunder its control. In this case the feed rate will then be at a maximumin the determined direction and will not vary there from. In this mannerthe tracer and cutter are gradually moved away out of contact with thework and pattern without an abrupt stop in their movement such as mightcause a mar on the finished surface. After the tracer and cutter havecleared the work the operator will move the starting lever to a stopposition to stop rotation of the cutter and operation of the pump.

An important advantage of the tracer mechanism utilized in this machineis that a punch may be formed directly from a die as shown in Figure 35;or the reverse that a die may be formed directly from a punch as shownin Figure 36. In such a case as shown in Figure 35 the tracer arm isadjusted so that the distance between the contact surface it of thetracer but ton and the center of the tracer head i2 is equa -l to theradius 3d? of the cutter used to machine the punch. As previouslyexplained, mechanism has been provided for maintaining the line Y-Y'always perpendicular to the tangent drawn through the point of contactwith the pattern and this will be true irrespective of the side of thecontour line that the cutting takes place. With this arrangement, it ispossible to place the center of the tracer head in the same position asthe center of the cutter even although the cutter is upon one side ofthe contour line and the tracer is contacting upon the opposite sidethereof. This produces the same effect as if thetracer button was ofzero diameter which is impossible with present known machines. Byreversing these parts, it will be seen that the re- Thestarting lever iton the side of the machine is verse operations may be carried out asshown in Figure 36.

Another important feature of this machine is its use as a die-sinkerwithout the necessity of making major changes to the machine after beingused for profiling purposes.

As will be understood it is necessary toef-- fect relative movementbetween the cutter and work in three directions when cutting dies andthe like, and this third movement is effected in the present casethrough elevation of the knee 65. The novel method of die-sinking usedherein consists of a continuous movement somewhat spiral in naturebetween the cutter and work from the moment that the cutter contacts thework until the finished die is produced. The relative movement in twodirections in a horizontal plane is accomplished by the mechanismalready described for profiling purposes, and the additional feedingmovement is effected automatically by coupling the hydraulic motor shownin Figure 8 to the elevating screw of the knee so that for each movementof 360 degrees between the work and cutter in a horizontal plane-thework will also be elevated or lowered a predetermined amount.

The hydraulic motor has connected therewith a shaft 268 which projectsthrough the housing 269 as shown in Figure 2 where it is coupled bymeans of bevel gears 210 to a vertical spline shaft 21L This splineshaft extends through a bracket 212 projecting from the rear of the kneewhich has journaled therein a second pair of bevel gears 213 and 214.These gears are mounted for free rotation with respect to the shaft 21!and a clutch member 215 is splined on the shaft for alternate engagementwith these gears for effecting rotation of a third bevel gear 216 inopposite directions. The bevel gear 216 is keyed to shaft 211 whichextends into a variable feed gear box 2l8 inserted in the side of theknee and provided with speed change levers 219 attached to the sidethereof. This variable feed box may be of any suitable construction andthe final shaft 283 thereof is provided with a bevel gear 28! meshingwith bevel gear 282 keyed to the upper endoi the elevating screw 282. Byadjusting the levers 2'l9lit will be apparent that the rate of verticalfeed of the knee for each spiral movement of the work and pattern aboutthe tracer and cutter respectively may be varied to suit the material orfinish desired. The clutch member 215 may be shifted by means of amanual control lever 284 to determine the direction of feeding movementof the knee. This lever is secured to the end of the horizontal shaft285 which has the shifter fork 286 secured thereto;

This shaft extends through the opposite side of the gear box 212 whereit is provided with a trip arm 281. A T-slot 288 is formed on the sideof the column for receiving trip dogs 289 which are adapted to cooperatewith the trip arm 281 to throw the clutch 215 to a neutral positionautomaticaliy after the die-sinking operation has been completed. If thedie-sinking has progressed by gradually moving the knee upward, it maybe returned to starting posiiion, after the clutch 215 has beenauioinatically positioned in a neutral position, by means of themanually rotatable lever :90 ecured to the end of the horizontal shaftjournalcd in the knee, and having on its inner end a bevel gear 292meshing with bevel gear 282. The shaft 285 may be provided with detentmechanism comprising a spring pressed plunger 293 for holding the clutchin any one of its three positions. Since the motor [29 is utilized torotate the tracer head, it will be apparent that the tracer head willonly make one complete revolution after the work has completed itsorbital movement thereabout and this will be true even. although theremay be some reverse movements during the progress of a completerotation. This motor may therefore be coupled to the knee to effectfeeding thereof and the resultant feed movement at the end of a completerotation of the work will be that determined by the setting of the feedbox 218.

From the foregoing description it should now be apparent that aprofiling and die-sinking machine tool has been produced having animproved tracer control mechanism which makes possible continuousoperation through angles of 360 degrees or greater, without attention onthe part of the operator, and in which the tracer is automaticallypositioned in contact with the work and which may be withdrawn fromcontact with the work without marring the same. construction also makespossible reproduction of work hitherto deemed impossible of reproductionby tracer controlled methods; easy conversion from one type of use toanother and the use of cutters of diiferent diameters from the tracerbutton. Attention is invited to the fact that the direction indicator onthe tracer head may also be utilized to aid in cutting an originaloutline under manual control without the aid of a pattern.

That which is claimed is:

1. A pattern controlled milling machine for reproducing work from apattern comprising a cutter, a power circuit for controlling thedirection of resultant feed movement between cutter and work in tworight angular paths or in any radial direction in the four quadrantsformed by the intersection of said paths including power actuablemotors, a rotatable power distributing element therefor, a single powerline connected to said element, means coupling the motors in parallel tosaid element for individual or simultaneous actuation, and tracercontrolled means for rotatably positioning said element to couple thepower line to one motor or simultaneously to all motors to effect a feedmovement selectively in the right angular paths or in the quadrantalpaths.

2. A pattern controlled milling machine for reproducing work from apattern comprising a cutter, a power circuit for controlling thedirection of resultant feed movement between cutter and work in rightangular paths or in any radial direction in the four quadrants formed bythe intersection of said paths including a plurality of power actuablemotors, a rotatable power distributing element therefor, means couplingthe motors in parallel to said element for individual or simultaneousactuation, power actuable means for effecting rotation of saiddistributing element, and tracer mechanism for controlling energizationof said power actuable means and thereby the direction of resultant feedmovement.

3. A pattern controlled milling machine for reproducing work from apattern comprising a cutter, a power circuit for controlling the di-1".3LlCl1 of resultant feed movement between cutta-r and work in rightangular paths or in any radial direction in the four quadrants formed bythe in rsection of said paths including power actuab c mctors, a powerdistributing element therefor, means coupling the motors in parallel tosaid element for individual or simultaneous This improved

